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Sperm

About: Sperm is a(n) research topic. Over the lifetime, 43420 publication(s) have been published within this topic receiving 1316145 citation(s).


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Journal ArticleDOI
12 Sep 1992-BMJ
TL;DR: There has been a genuine decline in semen quality over the past 50 years, and as male fertility is to some extent correlated with sperm count the results may reflect an overall reduction in male fertility.
Abstract: OBJECTIVE--To investigate whether semen quality has changed during the past 50 years. DESIGN--Review of publications on semen quality in men without a history of infertility selected by means of Cumulated Index Medicus and Current List (1930-1965) and MEDLINE Silver Platter database (1966-August 1991). SUBJECTS--14,947 men included in a total of 61 papers published between 1938 and 1991. MAIN OUTCOME MEASURES--Mean sperm density and mean seminal volume. RESULTS--Linear regression of data weighted by number of men in each study showed a significant decrease in mean sperm count from 113 x 10(6)/ml in 1940 to 66 x 10(6)/ml in 1990 (p < 0.0001) and in seminal volume from 3.40 ml to 2.75 ml (p = 0.027), indicating an even more pronounced decrease in sperm production than expressed by the decline in sperm density. CONCLUSIONS--There has been a genuine decline in semen quality over the past 50 years. As male fertility is to some extent correlated with sperm count the results may reflect an overall reduction in male fertility. The biological significance of these changes is emphasised by a concomitant increase in the incidence of genitourinary abnormalities such as testicular cancer and possibly also cryptorchidism and hypospadias, suggesting a growing impact of factors with serious effects on male gonadal function.

2,347 citations

01 Jan 1980
TL;DR: This laboratory manual consists of 2 sections which describe methods of examination of human semen and semen-cervical mucus interaction in order to standardize procedures and facilitate evaluation and comparison of research reports.
Abstract: This laboratory manual consists of 2 sections which describe methods of examination of human semen and semen-cervical mucus interaction in order to standardize procedures and facilitate evaluation and comparison of research reports The section on semen collection and examination discusses and makes recommendations for sample collection and delivery; initial examination; motility assessment estimation of sperm density; examination of particulate debris; agglutination; sperm viability; counting the spermatozoa; and analysis of morphological characteristics of germinal cells including preparation of seminal fluid smears staining method and classification and quantification of germinal cells and leucocytes Photomicrographs are provided to demonstrate morphological characteristics of normal and abnormal mature sperm immature germinal cells and leucocytes and epithelial cells Appendices provide information on frequency of various sperm forms in a normal ejaculate Papanicolaou staining procedure for sperm and the Bryan/Leishman stain for seminal fluid morphology smears A sample record for sperm analysis is also included The section on sperm-cervical mucus interaction describes the composition and characteristics of the mucus the collection procedure storage and preservation and evaluation including pH Methods of evaluating sperm-cervical mucus interaction are then described The timing and techniques of the post-coital test vaginal pool sample exocervical and low cervical samples and endocervical samples and their interpretation are discussed Instructions are provided for in vitro studies including the capillary tube test and the slide technique

2,122 citations

Book ChapterDOI
01 Jan 1998
TL;DR: This chapter discusses Sperm Competition in Birds, Sexual Selection in Spiders and Other Arachnids, and Reproduction, Mating Strategies and Sperm competition in Marsupials and Monotremes.
Abstract: General Themes: G.A. Parker, Sperm Competition and the Evolution of Ejaculates: Towards a Theory Base. A.P. Moller, Sperm Competition and Sexual Selection. W.G. Eberhard, Female Roles in Sperm Competition. J. Wright, Paternity and Paternal Care. Taxonomic Treatments: L.F. Delph and K. Havens, Pollen Competition in Flowering Plants. D.R. Levitan, Sperm Limitation, Gamete Competition and Sexual Selection in External Fertilizers. N.K. Michiels, Mating Conflicts and Sperm Competition in Simultaneous Hermaphrodites. B. Baur, Sperm Competition in Molluscs. M.A. Elgar, Sperm Competition and Sexual Selection in Spiders and Other Arachnids. L.W. Simmons and M.T. Siva-Jothy, Sperm Competition in Insects: Mechanisms and the Potential for Selection. C.W. Petersen and R.R. Warner, Sperm Competition in Fishes. T.R. Halliday, Sperm Competition in Amphibians. M. Olsson and T. Madsen, Sexual Selection and Sperm Competition in Reptiles. T.R. Birkhead, Sperm Competition in Birds: Mechanisms and Function. D.A. Taggart, W.G. Breed, P.D. Temple-Smith, A. Purvis, and G. Shimmin, Reproduction, Mating Strategies and Sperm Competition in Marsupials and Monotremes. M. Gomendio, A.H. Harcourt, and E.R.S. Roldan, Sperm Competition in Mammals. T.R. Birkhead and A.P. Moller, Sperm Competition, Sexual Selection and Different Routes to Fitness. Index.

2,047 citations

Journal ArticleDOI
TL;DR: These studies demonstrate capacitation of bovine sperm by heparin requires at least a 4-h exposure of sperm toHeparin and suggest that plasma membrane changes prior to an AR can be detected by exposure of bovo sperm to LC.
Abstract: Capacitation of bovine sperm was evaluated by determining the ability of sperm to fertilize bovine oocytes in vitro and to undergo an acrosome reaction upon exposure to lysophosphatidylcholine (LC). Incubation of sperm with heparin (10 micrograms/ml) increased the percentage of oocytes fertilized, but this required exposing sperm to heparin for at least 4 h before adding them to oocytes. There was no effect on the percentage of motile or acrosome-reacted sperm after exposure of noncapacitated sperm to 100 micrograms/ml LC for 15 min. When sperm were incubated for 4 h with heparin, exposure to 100 micrograms/ml LC for 15 min had no effect on the percentage of sperm that were motile, but the percentage of acrosome-reacted sperm increased from less than 10% to over 70%. The acrosome reactions (ARs) induced by LC were synchronous, reached maximal levels within 15 min, and differed (p less than 0.001) between sperm incubated under capacitating (with heparin) and noncapacitating conditions (without heparin). The time course required for heparin to capacitate sperm as judged by in vitro fertilization and to render sperm sensitive to LC induction of the AR were found to be similar. The percentage of ARs induced by LC and percentage of oocytes fertilized by sperm were found to be heparin-dose-dependent, with the maximum responses occurring at 5-10 micrograms/ml heparin. The correlation between the mean fertilization and LC-induced AR percentages was 0.997 (p less than 0.01). These studies demonstrate capacitation of bovine sperm by heparin requires at least a 4-h exposure of sperm to heparin and suggest that plasma membrane changes prior to an AR can be detected by exposure of bovine sperm to LC.

1,533 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202228
20211,697
20201,752
20191,638
20181,735
20171,594